scholarly journals Transcriptome Dynamics of Pseudomonas putida KT2440 under Water Stress

2011 ◽  
Vol 78 (3) ◽  
pp. 676-683 ◽  
Author(s):  
Gamze Gülez ◽  
Arnaud Dechesne ◽  
Christopher T. Workman ◽  
Barth F. Smets
Keyword(s):  
Gene Expression ◽  
Pseudomonas Putida ◽  
Unsaturated Soils ◽  
Water Deprivation ◽  
Expression Profiles ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Surface Model ◽  
Matric Potential ◽  
Peg 8000

ABSTRACTWater deprivation can be a major stressor to microbial life in surface and subsurface soil. In unsaturated soils, the matric potential (Ψm) is often the main component of the water potential, which measures the thermodynamic availability of water. A low matric potential usually translates into water forming thin liquid films in the soil pores. Little is known of how bacteria respond to such conditions, where, in addition to facing water deprivation that might impair their metabolism, they have to adapt their dispersal strategy as swimming motility may be compromised. Using the pressurized porous surface model (PPSM), which allows creation of thin liquid films by controlling Ψm, we examined the transcriptome dynamics ofPseudomonas putidaKT2440. We identified the differentially expressed genes in cells exposed to a mild matric stress (−0.4 MPa) for 4, 24, or 72 h. The major response was detected at 4 h before gradually disappearing. Upregulation of alginate genes was notable in this early response. Flagellar genes were not downregulated, and the microarray data even suggested increasing expression as the stress prolonged. Moreover, we tested the effect of polyethylene glycol 8000 (PEG 8000), a nonpermeating solute often used to simulate Ψm, on the gene expression profile and detected a different profile than that observed by directly imposing Ψm. This study is the first transcriptome profiling of KT2440 under directly controlled Ψmand also the first to show the difference in gene expression profiles between a PEG 8000-simulated and a directly controlled Ψm.

scholarly journals The Porous Surface Model, a Novel Experimental System for Online Quantitative Observation of Microbial Processes under Unsaturated Conditions

2008 ◽  
Vol 74 (16) ◽  
pp. 5195-5200 ◽  
Author(s):  
Arnaud Dechesne ◽  
Dani Or ◽  
Gamze Gülez ◽  
Barth F. Smets
Keyword(s):  
Liquid Film ◽  
Liquid Medium ◽  
Real Time ◽  
Single Cells ◽  
Liquid Films ◽  
Microbial Processes ◽  
Porous Surface ◽  
Surface Model ◽  
Ceramic Plate ◽  
Matric Potential

ABSTRACT Water is arguably the most important constituent of microbial microhabitats due to its control of physical and physiological processes critical to microbial activity. In natural environments, bacteria often live on unsaturated surfaces, in thin (micrometric) liquid films. Nevertheless, no experimental systems are available that allow real-time observation of bacterial processes in liquid films of controlled thickness. We propose a novel, inexpensive, easily operated experimental platform, termed the porous surface model (PSM) that enables quantitative real-time microscopic observations of bacterial growth and activity under controlled unsaturated conditions. Bacteria are inoculated on a porous ceramic plate, wetted by a liquid medium. The thickness of the liquid film at the surface of the plate is set by imposing suction, corresponding to soil matric potential, to the liquid medium. The utility of the PSM was demonstrated using Pseudomonas putida KT2440 tagged with gfp as a model bacterium. Single cells were inoculated at the surface of the PSM, and the rate at which colonies expanded laterally was measured for three matric potentials (−0.5, −1.2, and −3.6 kPa). The matric potential exerted significant influence on colony expansion rates, with a faster rate of spreading at −0.5 than at −1.2 or −3.6 kPa (diameter increase rate, ca. 1,000, 200, and 17 μm h−1, respectively). These differences can be attributed to cell motility, strongly limited under the most negative matric potential. The PSM constitutes a tool uniquely adapted to study the influence of liquid film geometry on microbial processes. It should therefore contribute to uncovering mechanisms of microbial adaptation to unsaturated environments.

1327: Gene Expression Profiles in Benign Prostatic Hyperplasia

2004 ◽  
Vol 171 (4S) ◽  
pp. 349-350
Author(s):  
Gaelle Fromont ◽  
Michel Vidaud ◽  
Alain Latil ◽  
Guy Vallancien ◽  
Pierre Validire ◽  
...  
Keyword(s):  
Gene Expression ◽  
Benign Prostatic Hyperplasia ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Prostatic Hyperplasia

The Oral Intake of Organic Germanium, Ge-132, Elevates α-Tocopherol Levels in the Plas-ma and Modulates Hepatic Gene Expression Profiles to Promote Immune Activation in Mice

2014 ◽  
Vol 84 (3-4) ◽  
pp. 0183-0195 ◽  
Author(s):  
Takashi Nakamura ◽  
Tomoya Takeda ◽  
Yoshihiko Tokuji
Keyword(s):  
Gene Expression ◽  
Immune Activation ◽  
Expression Profiles ◽  
Water Soluble ◽  
Alpha Tocopherol ◽  
Hepatic Gene Expression ◽  
Tocopherol Concentration ◽  
Altered Expression ◽  
Atp Production ◽  
Transfer Protein

The common water-soluble organic germanium compound poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) exhibits activities related to immune responses and antioxidant induction. In this study, we evaluated the antioxidative effect of dietary Ge-132 in the plasma of mice. Male ICR mice (seven mice per group) received an AIN-76 diet with 0.05 % Ge-132; three groups received the Ge-132-containing diet for 0, 1 or 4 days. The plasma alpha-tocopherol (α-tocopherol) concentration increased from 6.85 to 9.60 μg/ml after 4 days of Ge-132 intake (p < 0.05). We evaluated the changes in hepatic gene expression related to antioxidative activity as well as in the entire expression profile after one day of Ge-132 intake, using DNA microarray technology. We identified 1,220 genes with altered expression levels greater than 1.5-fold (increased or decreased) as a result of Ge-132 intake, and α-tocopherol transfer protein (Ttpa) gene expression was increased 1.62-fold. Immune activation was identified as the category with the most changes (containing 60 Gene Ontology (GO) term biological processes (BPs), 41 genes) via functional clustering analysis of altered gene expression. Ge-132 affected genes in clusters related to ATP production (22 GO term BPs, 21 genes), lipid metabolism (4 GO term BPs, 38 genes) and apoptosis (5 GO term BPs). Many GO term BPs containing these categories were significantly affected by the Ge-132 intake. Oral Ge-132 intake may therefore have increased plasma α-tocopherol levels by up-regulating α-tocopherol transfer protein (Ttpa) gene expression.

HEAT TRANSFER IN THIN LIQUID FILMS FLOWING DOWN HEATED INCLINED GROOVED PLATES

2010 ◽  
Vol 2 (5) ◽  
pp. 455-468 ◽  
Author(s):  
Hongyi Yu ◽  
Karsten Loffler ◽  
Tatiana Gambaryan-Roisman ◽  
Peter Stephan
Keyword(s):  
Heat Transfer ◽  
Liquid Films ◽  
Thin Liquid Films
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